Dual display weight measuring apparatus which detects movement of the pointer through slits in the mechanical dial face

ABSTRACT

A mechanical weighing scale having mechanical parts driving a pointer rotating around a fixed disc or dial having slots or holes formed therein. The mechanical pointer operates to provide an analog display of one&#39;s weight to the user. An optical sensor system is responsive to the mechanical motion of the mechanically-rotating pointer as it passes over each of the holes or slots for determining a number of counts associated with the mechanical motion of the rotating pointer and translating the counts to a corresponding weight value for display onto a digital display.

This application claims the benefit of priority from commonly owned U.S.Provisional Application Serial No. 60/272,139, filed Feb. 28, 2001, forDUAL DISPLAY WEIGHT MEASURING APPARATUS.

FIELD OF INVENTION

The present invention relates to measurement devices in general and moreparticularly to a weight measuring apparatus having both analog anddigital output displays for displaying the weight of a user.

DESCRIPTION OF PRIOR ART

There exists in the prior art numerous methods and apparatus formeasuring and displaying body weight. For example, various types ofplatform scales have been designed and manufactured by scalemanufacturers. These scales include a conventional mechanical analogscale having a base and a platform movable relative to the base. A leverstructure is movable with the platform for causing rotation of a dial.Angular rotation of the dial represents weight on the platform which isindicated by numerical indicia on the dial and is visible through awindow in the platform. U.S. Pat. No. 5,141,065 entitled WEIGHTACTIVATED PLATFORM SCALE issued Aug. 25, 1992 to Maxwell et al.discloses an electronic-mechanical version that replaces a rotary dialdisplay with a digital readout. The dial forms part of an electricalencoder. As is conventionally understood, the encoder may take one oftwo known forms, namely a pulse count type which counts pulsesrepresenting angular movement, or an encoded type in which the dial isprovided with a coded pattern. The coded pattern indicates angularposition which is read by a sensor and converted to a measure of weight.Lastly, a strain gauge type scale includes a strain gauge for measuringpressure applied on the platform which is converted to an electricalsignal applied to a digital readout.

While the prior art includes both mechanical analog scales as well aselectronic digital scales for measuring and displaying a user's weight,a need in the art exists to provide a user with the option to measureand view the measured weight through either digital or analog means.

SUMMARY OF THE INVENTION

The invention is embodied in a mechanical weighing scale havingmechanical parts driving a pointer rotating around a fixed disc or dialhaving slots or holes formed therein. The mechanical pointer operates toprovide an analog display of one's weight to the user. An optical sensorsystem is responsive to the mechanical motion of themechanically-rotating pointer as it passes over each of the holes orslots for determining a number of counts associated with the mechanicalmotion of the rotating pointer and translating the counts to acorresponding weight value for display onto a digital display. Theoptical sensor system includes a series of photo detectors placedunderneath corresponding ones of the holes or slots, and operates fordetecting when the pointer passes over a corresponding slot on the dialso as to trigger an electrical signal which functions as a pulse countto a microprocessor unit. Each time the pointer passes over a slot, acorresponding photo detector is triggered causing a pulse count to besent to the microprocessor. When the pointer stops rotating,corresponding to a given weight value, the microprocessor totals thenumber of pulse counts and converts that to a digital weightrepresentation. In this manner the scale has both a visual analog outputindicated by the pointer's angular position as well as a digital displayoutput corresponding to the number of pulses sensed by the opticalsensor system due to the rotating pointer.

Alternatively, the invention is embodied in a mechanical weighing scalehaving mechanical parts responsive to a weight disposed thereon fordriving a rotatable shaft. A pointer coupled to the shaft rotates inaccordance with the shaft about a fixed disk having indicia thereon fordetermining an analog representation of a user's weight. A rotatabledisc or wheel is also coupled to the rotatable shaft for rotatingtherewith. The disc or wheel includes slots or holes formed therein. Anoptical sensor disposed at a fixed position relative to the rotatablewheel operates to sense the mechanical rotation of the wheel via theslots or holes formed therein and determines a number of countsassociated with the mechanical motion and translates the counts to acorresponding weight value for display onto a digital display via adigital processor. The optical sensor comprises a photo detector fixedlypositioned relative to the rotating disc or wheel to detect wheelmovement via the corresponding holes or slots thereon so as to triggeran electrical signal which functions as a pulse count to amicroprocessor unit. Each time a slot on the disc passes over the photodetector, the detector is triggered causing a pulse count to be sent tothe microprocessor. When the disc stops rotating, corresponding to agiven weight value, the microprocessor totals the number of pulse countsand converts that to a digital weight representation for display.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a top plan view of the dual display weight scale according tothe present invention.

FIG. 1B is a top plan view of the dual display weight scale with theweight receiving platform removed showing conventional internalstructure of the scale.

FIG. 2 is a schematic illustration of the dual display system accordingto an embodiment of the present invention.

FIG. 3 is a schematic illustration of the dual display system accordingto an alternative embodiment of the present invention.

FIG. 4 is a schematic illustration of the structural configuration forsupporting the dual display system according to the present invention.

FIG. 5 is a block diagram illustrating a switch for selectivelydisplaying analog or digital output data according to an aspect of thepresent invention.

FIG. 6 is a block diagram of the major functional components of the dualdisplay system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As shown in the drawings, and in particular, with reference to FIGS. 1Aand 1B, a mechanical platform bathroom scale comprises a conventionalbase 10 formed from a stamped metal sheet, for example, foraccommodating a mechanical scale mechanism, and a platform 20 adapted tobe disposed over the base and coupled thereto via hangers 25 inconventional fashion. The platform 20 provides a weight receivingsurface upon which a person may stand. In conventional fashion, weightis then transferred by the metal hangers to various levers within thescale mechanism to cause the levers and calibrating plate 15 to movetoward the base. The operation of such a conventional mechanical scaleis disclosed in U.S. Pat. No. 5,141,065 entitled WEIGHT ACTIVATEDPLATFORM SCALE issued Aug. 25, 1992 to Maxwell et al.

As disclosed therein, and as shown in FIG. 1B, the weight sensingmechanism of a conventional mechanical scale 10 comprises a pair ofprimary levers 14 and a pair of secondary levers 16 arranged ininterconnected fashion and resting upon slots 13. The pair of primarylevers 14 are joined to calibrating member or plate 15. The primarylevers are each arranged on edge relative to the base and 15 have aninverted V-notch,(not shown) across the thickness of the lever materialto rest upon the slots 13 at the rear of the base 10.

The secondary levers 16 have inverted V-notch portions (not shown) whichrest upon the slots 13 in the front of the base 10. The other end ofeach of the secondary levers 16 is connected to and hangs below aprimary lever 14 intermediate its ends by means of a bracket 18. Each ofthe primary and secondary levers 14 and 16 has a V-portion 19 locatedadjacent to the corner portion which supports the levers and is adaptedto support metal hangers 20 which rest in the V-portion of eachrespective lever.

The weight-sensing mechanism is mounted on a channel support 30 securedto the base 10. In accordance with an aspect of the present invention,rotary dial 27 (see FIG. 2) is turned by shaft 32 which is part of androtated by a pinion gear 33. The pinion gear 33 is turned by asubstantially horizontally extending rack 34 which is pivotally securedto lever 35. The lever 35 comprises a bracket pivotally supported on arod 36 extending transversely through the crank sides and pivotallyjournaled in a support member 37. The rack 34 is pivotally connected at38 to a lower end of the crank 35 to move with movement of the bellcrank 35 and is held in engagement with pinion gear 33 by means of aspring 39 connected at 40 to a side wall of the base and connected at 41to the rack 34.

A coil detention spring 42 is mounted upon a swivel post 43 which isloose and capable of moving on the bottom coils of the spring 42threadably supporting the calibrating plate 15. The post 43 has a slot44 across its upper end for receiving and supporting top end of the coilspring 42. A kick switch 60 is located on a side wall of the scale forturning on the electronic or digital readout of the scale. Uponactuation, an internal electrical circuit is energized so as to set orreset the electronic display to zero. Power on/off switch 65 may be usedin conventional fashion to enable/disable energy from a power sourcesuch as a battery (not shown).

As shown in FIG. 1A, platform portion 20 further includes a displayportion comprising an analog display and a digital display. The analogdisplay comprises a disc 400 (i.e. dial) or wheel over which passes arotatable pointer for determining a measured weight of a user. Thedigital display comprises an LCD display for example coupled toappropriate electronic circuitry including a microprocessor for example,for providing a digital readout determining a measured weight of a user.A transparent window area 26 on the surface of the platform comprising aplastic, for example, permits viewing of the analog and digitaldisplays, located beneath platform 20 by the user.

As shown in FIG. 2, the scale includes an optical pulse counter whereindial 27 configured as a circular disc has a plurality ofcircumferentially spaced, radially extending tabs 50 defining slots 52therebetween. An optical sensing system is configured as an opticalinterrupter 54 comprising two photosensing elements arranged inconventional fashion for sensing rotary movement of the dial 27 andgenerating pulse signals in response thereto. The optical interrupter 54includes a support 56 carrying the photosensitive elements.

According to an aspect of the present invention, shaft 32 of the basescale structure 10 (of FIG. 1B) extends through rotary dial 27. Shaft 32also extends through a first circular cavity 410 of substantially flatdisk 400 having indicia thereon as shown in FIG. 1A.

Disk 400 further includes a second cavity 320 formed as a window toaccommodate LCD display 330 for displaying a digital output weightmeasurement to the user based on the rotating dial 27 and opticalsensing system. A rotary pointer 300 has a stem portion (not shown)adapted to receive the top end of shaft 32 for securing thereto whichoperates to couple the pointer to the shaft such that rotation of theshaft 32 causes a corresponding rotation of the pointer. In this manner,the rotatable pointer points to the corresponding indicia on flat disk400 associated with the measured weight of the user based on themechanical weight sensing mechanism due to rotation of the shaft 32.

Contemporaneous with rotation of the rotatable pointer about fixed flatdisk 400, the optical sensor system coupled rotatable disc 27 operatesto count the number of pulses associated with rotation of disc 27 andprovide the information to a processor 650 and associated electronicssuch as a microprocessor for display via digital display device 330 suchas an LCD as shown herein.

In this manner, a user is presented with both an analog output via themechanical pointer 300 and shaft 32 via fixed disk 400, as well as adigital output of the user's weight based on rotation of disc 27,optical sensor system, microcontroller unit and LCD display. FIG. 6provides a schematic block diagram depicting the general processing anddisplay of information associated with the dual analog and digitalmeasurement and display of a user's weight comprising a mechanicalweighing scale actuator 600 for driving a pointer on dial arrangement610 for providing an analog display 620. The dial arrangement includesslots such that an optical sensor 630 positioned relative to the dialarrangement provides a signal such as a pulse count responsive to themovement of the pointer over the slots which is provided to processor650 for appropriate conversion to a digital display 660 provided to theuser.

FIG. 4 illustrates the structural configuration for supporting the dualdisplay system of the present invention. As shown in FIG. 4, bridge 500spans the dial 27 and channel 30 and includes a pair of planarhorizontal segments 510 that support the digital display device 330(i.e. digital display device 330 and microprocessor 650 have supportingportions resting thereon) and a pair of elevated planar horizontalmembers 520 (elevated relative to members 520) for supporting fixed disk400 (or 400′). The bridge has planar side portions 530 secured to thebase via conventional means, such as rivets, welds or other well knownsecuring methods. Vertically extending segments 540 each connect acorresponding one of the substantially planar horizontal segments 510with a given end of each of the side portions 530. Elevated planarmembers 520 are elevated from planar horizontal segments 510 by means ofvertical wall segment 550. A gap or space 522 is formed between elevatedplanar horizontal members 520 to accommodate shaft 32. In this manner,bridge 500 provides a support platform for both the fixed disk and thedigital display device.

In an alternative embodiment, the dual display scale system according tothe invention may be modified in the following manner. As shown in FIG.3, fixed flat disk 400′ comprises, in addition to the indicia thereoncorresponding to numeric values for a user's weight pointable theretovia rotatable pointer 300, corresponding slots or holes 4201 formedtherein at predetermined portions or intervals on the disk which may bepassed over via pointer 300. A series of photodetectors (not shown) aredisposed beneath each of the corresponding holes or slots 4201 on fixeddisk 4001 and are operable for detecting when the pointer passes over acorresponding slot on the fixed disk. This triggers an electrical signalwhich functions as a pulse count to the microprocessor unit. Each timethe pointer 300 passes over a slot 4201, the slot is at least partiallycovered by the pointer, thus interrupting the ambient light from thetransparent window 26 at the top of the scale. The correspondingphotodetector is triggered causing a pulse count to be sent to themicroprocessor. When the pointer stops rotating, corresponding to agiven weight value, the microprocessor totals the number of pulse countsand converts that to a digital weight representation. In this manner thescale has both a visual analog output indicated by the rotatablepointer's angular position and corresponding indicia on disk 400′, aswell as a digital display output corresponding to the number of pulsessensed by the optical sensor system due to the rotating pointer passingover fixed disk 400′. Such a configuration eliminates the need for therotating disc 27 shown FIG. 2. In addition, the above-describedconfiguration eliminates the need for a separate electronic photoemitting device. It should be noted, however, that a configurationhaving separate photo emitters and detectors disposed, respectively,above and beneath each of the slots on fixed disk 4001 for sensing themotion of the pointer of the slots and providing a corresponding pulsecount to a processor for digital display is also contemplated.

As shown in schematically in FIG. 5, the dual display system of thepresent invention may be modified so as to enable a user to selectivelydetermine the type of measurement and output display associated with themechanical bathroom scale of the present invention. For example, auser-activatable switch 500 may be disposed on a side portion of thebase 10 and operatively coupled (e.g. electrically and/or mechanicallycoupled) to both the analog and digital mechanisms within the scale soas to selectively activate or inactivate either the digital or theanalog output display of the user's weight. For example, the switch 500may be operatively coupled to both the pointer 300 (via mechanical orelectromechancial coupling, for example) and to the microprocessor 650or LCD output display (via electrical coupling, for example) at a firstsetting or position 1 such that the weight of a user is sensed in themanner described above and output to the user at both displays (module510).

Alternatively, placing the switch 500 in a second position 2 causes acontrol signal to be sent to the microcontroller 650 for inhibitingdisplay of the LCD (module 520) via the optical sensing system describedabove. In this case, only an analog readout out of the user's weight isobtained via the rotating pointer.

In a third case, placing the switch 500 in a third position 3 may causea mechanical (or electromechanical, for example) motion or retraction ofthe stem of pointer 300 from shaft 32. This may be accomplished througha variety of methods well known in the art to decouple the stem portionof the pointer from the rotatable shaft to permit shaft rotation withoutthe corresponding rotation of the pointer. For example, a mechanicalactuator responsive to the position switch may effect a verticaldisplacement of the pointer relative to the shaft so as to decouplethese elements, thereby preventing rotation of the pointer andinhibiting analog display (module 530).

Alternatively, the pointer may be constricted circumferentially aboutthe shaft via a retractable ring, for example, such that retraction ofthe ring results in a corresponding expansion of the circumference ofthe pointer, thereby enabling rotation of the shaft withoutcorresponding pointer rotation. In this case, selective disabling of theanalog pointer allows only a digital readout out of the user's weight tobe obtained via the LCD display.

It is to be understood that the user-activatable switch described aboveneed not include all three selection positions. For example, the switchmay be implemented with only the first and third selection positionsdescribed herein in accordance with the first embodiment described aboveand illustrated in FIG. 2. Alternatively, the second embodiment asillustrated in FIG. 3, may be implemented using only the first andsecond selection switch positions, since in the second embodiment therotational pointer 300 is also utilized in determining the digitaloutput display via the optical sensing system.

It is to be understood that one skilled in the art may make manyvariations and modifications to that described herein. For example, acantilever beam load cell under the spring that drives the wheel may beadded, relative to the rotating dial. Additional electronic circuitrymay also be added so as to determine body fat, body mass index based onthe calculated weight from the mechanical scale. All such variations andmodifications of the above components and structures are intended to beincluded within the scope of the invention.

I claim:
 1. A mechanical weighing scale comprising: mechanical membersincluding a spring member for sensing a weight on a platform and drivinga pointer coupled thereto; a fixed disc having indicia thereon andhaving slots formed therein, said pointer driven about a top surface ofsaid fixed disc so as to sequentially pass over said slots, said pointerdriven such that the indicia pointed to by said pointer corresponds tothe sensed weight for visual display to a user; an optical sensorresponsive to the mechanical motion of the mechanically-rotating pointeras it passes over each of the slots for generating a signal indicativeof a count in response thereto; and a processor responsive to saidgenerated signals for determining a number of counts associated with themechanical motion of the rotating pointer and translating the counts toa corresponding weight value for display onto a digital display.